Judging Distances

Every Scout should be able to judge distance from an inch up to a mile and more.

If you remember your self measures accurately, they are a great help to you in measuring things. Also it is useful to cut notches in your staff, showing such measurements as one inch, six inches, one foot and one yard. These you can measure off with a tape measure before you use your staff.

Judging the distance of a journey is generally done by seeing how long you have been travelling, and at what rate. Suppose you walk at the rate of four miles an hour. If you have been walking for an hour and a half you know that you have done about six miles.

Distance can also be judged by sound. If you see a gun fired in the distance and you count the number of seconds between the flash and the sound of the explosion reaching you, you will be able to tell how far off you are from the gun, Sound travels at the rate of 365 yards in a second-as many yards as there are days in the year.

Test the following from your own observations.

At 50 yards, the mouth and eyes of a person can be clearly seen. At 100 yards, eyes appear as dots. At 200 yards, buttons and details of uniform can still be seen. At 300 yards, the face can be seen. At 400 yards, the movement of the legs can be seen. At 500 yards the colour of the uniform can be seen.

For distances over these, think out for yourself which point is half-way to the object. Estimate how far this may be from you, and then double it to obtain the distance. Another way is to estimate the farthest distance that the object can be away, and the very nearest it could be, and strike a mean between the two.

Objects appear nearer than they really are when the light is bright and shining on the object; when looking across water or snow; when looking uphill or down. Objects appear farther off when in the shade; when across a valley; when the background is of the same colour; when the observer is lying down or kneeling; when there is a heat haze over the ground.

Distances Across a River

The way to estimate the distance across a river is to notice an object X, such as a tree or rock, on the bank opposite to where you stand at A (see diagram). Start off at right angles to A X, and walk, say, ninety yards along your bank. On arriving at sixty yards, plant a stick or stone, B. On arriving at C, thirty yards beyond B and ninety from the start at A, turn at right angles and walk inland, counting your steps until you bring the stick and the distant tree in line. The number of steps you have taken from the bank, C D, will then give you the half distance across A X.